Article History
Received: 4 May 2018
Accepted: 10 October 2018
First Online: 23 October 2018
Compliance with ethical standards
: The experiments in this study were conducted in accordance with the German legislation on protection of animals and the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised 1996). The protocol for the Langendorff experiments was approved by the local Animal Ethics Committee (Project No. O 27/11).